Macrophage has a function of treating waste products in a human body and a defensive function against pathogens such as a microbe and a virus, and tumor cells. Macrophage also has a function as an effector of cell immunity via presentation of an antigen to T cell and production of interleukin 1. Accordingly, it is important to activate macrophage for treatment and prevention of a cancer and an infectious disease, and the activation of macrophage makes it possible to carry out treatment and prevention of a cancer and an infectious disease.
A factor for activating macrophage is, for example, an interferon, and its clinical application has been carried out. In addition, it is known that a certain kind of polysaccharides has an immunostimulating activity, and some of them are expected to be developed as an antiviral agent and an anticancer agent (Patent Document 1 or 2).
Further, a cancer advances via the steps of initiation (first stage, immortalization), promotion (second stage, growth) and progression (third stage, metastasis and invasion), and among these stages, it is the progression stage that has a relation to angiogenesis. Therefore, metastasis and invasion of a cancer can be suppressed by inhibiting the angiogenesis, and a medicament taking such an effect is useful as an inhibiting agent and a prophylactic agent for metastasis of a cancer.